Gear honing machine



July 4, 1961 Filed Jan. 5, 1959 W. S. PRAEG GEAR HONING MACHINE 2 Sheets-Sheet 1 INVENTOR.

ATTO NEYS July 4, 1961 Filed Jan. 5, 195

Flea.

W. S. PRAEG GEAR I-IONING MACHINE 2 Sheets-Sheet 2 ATTOR 2,990,657 GEAR HONING MACHINE Walter S. Praeg, Detroit, Mich., assignor to National Breach & Machine Company, Detroit, Mich., a corporation of Michigan 7 Filed Jan. 5, 1959, 'Ser. No. 784,947 4 Claims. (Cl. 51-105) The present invention relates to a gear honing machine, and more particularly to a machine including means providing automatically for proper crossed axes relationsh p between a hone and a series of gears as the hone wears in use.

It is an object of the present invention to provide a gear .honing machine including a pair of rotary spindles for supporting a gear and gear-like hone in mesh, means for causing approach between said spindles with a predetermined controlled force, swivel means mounting one of said spindles for angular adjustment about an axis perpendicular to the axes of said spindles, and means for locking the swivel support in angularly adjusted position.

More specifically, it is an object of the present invention to provide a gear honing machine as described in the preceding paragraph in which the swivel means includes anti-friction means effective to provide for angular adjustment of the swivel support as a result of pressure contact between the teeth of a meshed gear and gearlike hone carried by said spindles.

It is a further object of the present invention to provide a gear finishing machine as described in the foregoing including locking means preferably in the form of a brake for preventing angular displacement of the swivel support during a gear finishing operation.

It is a further object of the present invention to provide automatic means responsive to approach between a pair of relatively angularly movable spindles for effecting relative angular adjustment between said spindles to compensate for wear of a helical gear-like hone carried by one of said spindles and in mesh with a work gear carried by the other of said spindles.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, illustrating preferred embodiments of the invention, wherein:

FIGURE 1 is an elevational view of a gear honing machine.

FIGURE 2 is an enlarged elevational view partly in section, showing means for biasing the gear and tool together.

FIGURE 3 is an enlarged fragmentary elevational view partly in section.

FIGURE 4 is a fragmentary view looking in the direction of the arrows 4-4, FIGURE 3.

FIGURE 5 is a diagrammatic view showing an alternative form.

The present invention relates to an operation known as gear honing in which a gear-like tool, preferably after heat treatment or other hardening operation, is run in mesh with a gear-like hone. A hone is a tool in the form of a gear having at least its toothed portions formed of a relatively hard but slightly yieldable and highly resilient resin having abrasive particles separately embedded therein.

The operation is carried out by driving either the gear or the hone in rotation thereby driving the other of the members which is mounted for substantially free rotation. During meshed rotation between the gear and hone a rela tive traverse is carried out in a plane parallel to the axes of both spindles to insure distribution of the finishing action of the hone fromend to end of the gear teeth.

" ite States v Patent 2 This relative traverse is normally in a direction parallel to the axis of the gear.

To insure the pressure contact between the teeth of the gear and hone necessary to produce a gear finishing operation, one of the spindles is mounted for movement toward and away from the other spindle, and means are provided for applying a controlled force to move the said other spindle so as to estabish a predetermined pressure contact between the teeth of the gear and hone.

The hone is essentially an abrasive tool and in finishing a series of identical gears, the hone wears appreciably. Accordingly, as the hone wears, the center distance between the gear and hone decreases and throughout the life of the hone a very substantial decrease in center distance will take place.

As is well understood, a pair of cylindrical gears having diiferent helix angles may mesh with their axes crossed in space. It is common practice to refer to the helix angle of a gear, by which is meant the helix angle at the pitch line thereof. As a matter of fact, since the lead of the gear teeth is a constant factor, the helix angle of a gear tooth varies from the root to the crest thereof. Accordingly, as a hone wears away in use and its operating center distance with respect to work gears is reduced, there is an effective change in helix angle of the hone.

While there is some tendency for a hone as it is consumed in use, to have its teeth wear away in such a manner as to cause the helix angle toconform to the average helix angle of the gear, this is an unsatisfactory way to bring about true meshing relation, since it inherently means that the gear andtool are never quite properly helically aligned. This in turn results in rapid consumption of the hone.

In accordance with the present invention one of the spindles, preferably the hone supporting spindle, is mounted for relatively free angular adjustment about an axis perpendicular to the axes of the gear and hone. With the spindle thus freely supported, the gear and hone are brought into tight mesh at a predetermined pressure contact and this pressure contact is effective to swivel the hone into proper helical alignment with. the teeth of the gear. Thereafter, locking means are actuated to prevent angular movement of the hone during a gear finishing operation.

With the foregoing general description in mind there is shown a gear finishing machine 10 comprising a base 12, a column 14, and a forwardly projecting overhanging frame portion 16. A knee 18 is carried by the frame for vertical adjustment and at its top is provided with a slide 20 having a tilt table 22 carried at its upper side. Suitable means, such for example as a vertically extending feed screw 24 is provided for effecting vertical adjustment of the knee 18. Vertical adjustment of the knee 18 may be by suitable manual means such for example as bevel gearing terminating in a squared shaft end 26 for operation by a hand wheel.

The tilt table 22 is provided with a pivot connection 28 to an upstanding arm 29 on the slide 20. The axis of the pivot connection 28 is close to a horizontal plane passing through the axis of the work gear, as will subsequently be described, so that tilting of the table 22 about the axis of the pivot connection 28 results in essentially vertical movement of the work gear.

Mounted on the tilt table 22 are stocks 30 providing a free spindle support 31 for rotating the work gear G.

Secured to the underside of the'overhanging frame portion 16 is an adjustable tool head 32 having a spindle 34 for carrying a honing tool T. Received within the overhanging frame portion 16 is a motor which is con nected by suitable gearing (not shown) to effect positive rotation of the tool T and hence to drive the gear G through the intermeshed rotation of the parts.

During the meshed rotation of the gear and tool T the slide is traversed in a direction occupying a plane parallel to the axis of the gear and tool. For simplicity in FIGURE 1 the axes of the gear and tool are shown as parallel but in practice the helix angle of the hone will be selected such as to produce a crossed axes relationship between the gear and hone when meshed. This crossed axes relationship is of course provided by swiveling the hone or tool head 32 about a vertical axis perpendicular to and intersecting the axes of the spindles 31 and 34. The direction of traverse of the slide 20 is preferably horizontal and parallel to the axis of the gear G.

In order to carry out the honing operation under sufficient pressure contact to remove material from the surface of the hardened teeth of the gear G, the slide 20 is provided with a forwardly extending rigid ledge 36 and pressure control means indicated generally at 38 are provided. This means is best illustrated in FIGURE 2.

The pressure control means comprises a cylinder 40 fixedly carried at the forward edge of the tilt table 22 and having a movable piston 42 therein. The piston 42 projects downwardly below the lower end of the cylinder 40 and has a rounded projecting portion 44 which rests upon the upper surface 46 of the rigid ledge 36. The piston 42 includes an intermediate reduced portion 48 engageable by a pressure actuated brake element 50 connected to a plunger 52 actuated by a piston 54 movable in a cylinder 56. In operation, fluid under a controlled pressure is admitted through a port 58 and preferably simultaneously through a smaller restricted port 60. The pressure thus trapped in the cylinder 40 above the piston 42 lifts the tilt table with a force dependent upon the controlled pressure of the fluid.

In some cases the honing operation may be carried out with the hone and gear maintained in pressure contact by continued application of fluid pressure to the cylinder 40. In other cases it is dmirable to bring the gear and hone into initial contact at a controlled pressure determined by the fluid pressure admitted to the cylinder 40, after which the piston 42 is locked against movement by supplying fluid under pressure to the cylinder 56 to actuate the brake 50.

The foregoing mechanism is described in detail in prior copending application Serial No. 661,727, assigned to the assignee herein.

The present invention represents the addition of mechanism to the gear honing machine shown in FIGURES l and 2 so as to provide for continuous proper angularity between the axes of the gear and hone as the hone is consumed While finishing a multiplicity of like gears. It may be mentioned at this time that hones may operate to finish thousands of work gears before being sufficiently consumed to be discarded.

Referring now to FIGURES 3 and 4, the motor provided in the overhanging frame portion 16 is connected to a vertically extending drive shaft 62 connected to a bevel gear 64 meshing with a second bevel gear, a portion of which is indicated at 66. The bevel gear 66 is one of a train of gears connecting to the spindle 34 of the honing tool T.

Means are provided mounting the tool head 32 for very free rotation or angular adjustment about the axis of the shaft 62. This means comprises a bearing spacer collar 68 extending upwardly into an enlarged opening 70 at the underside of the frame portion 16 and is retained in place by screws 72. The tool head 32 has bolted or otherwise secured thereto as indicated at 74, a collar 76 provided with a radially outwardly extending flange 78 at its lower end engageable with the lower inner bearing race 80. It is provided at its upper end with a threaded ring 82 engaging with the upper end of the inner upper bearing race 84. A bearing spacer 86 is provided intermediate the races 80 and 84. With this arrangement it will be observed that the entire tool head 32 is swiveled in the ball bearings including the races and 84 for extremely free rotation.

The bevel gear 64 includes an upwardly extending sleeve portion 88 received in bearings indicated generally at 90 for supporting the lower end of the hone drive shaft 62.

In order to prevent angular movement of the tool head 32 during a honing operation a plate 92 is fixedly secured to the underside of the frame portion 16. Pivoted to the plate '92 as indicated at 94, is a brake arm 96 having a brake shoe 98 engageable with a circular cross-section surface 100 of the tool head 32. A toggle comprising links 102 and 104 is provided, the link 102 being pivoted to the movable end of the brake arm 96 at 106, and the link 104' being pivoted to the fixed plate 92 at 108. The links 102 and 104 are interconnected by a pivot which also serves as the connection for a piston rod 112 including a piston movable in a fluid cylinder 114 which in turn is pivoted at 116 to a cylinder supporting arm 118. When fluid under pressure is admitted to the cylinder 114 above the piston therein to move the toggle links to the extended position shown in FIGURE 4 it will of course be understood that it is a powerful application of braking pressure which prevents angular adjustment of the tool head 32.

In use the fluid cylinder 11-4 is operated to brake actuating position only after the pressure applying mechanism 38 has been operated to bring the gear G and hone T into tight mesh at a predetermined pressure. At this time since no braking pressure opposes swiveling of the tool head 32, it will swing to precisely the required position to cause the teeth of the gear and hone to be in true and perfect alignment. While the pressure between the gear and hone is maintained to hold the tool head in proper angularly adjusted position, fluid is admitted to the cylinder 114 to apply the brake, thus locking the tool head 32 in angularly adjusted position.

Thereafter, the honing operation may take place with pressure continuously applied to the cylinder 40 to cause the hone to follow up and maintain substantially uniform pressure contact with the gear. Alternatively, if fluid is admitted to the cylinder 56 the tilt table 22 will be blocked in its adjusted position. In either case, following the honing of a gear the tilt table is lowered to remove a finished work gear and a new work gear is replaced on the spindle 3'1. Thereafter, the tilt table 22 is elevated to establish predetermined pressure between the teeth of the gear and tool, thus effecting a required adjustment of the tool head 32 into the exact angular position required, after which the brake 100 is operated to lock the head 32 in adjusted position.

Theoretically, some material is removed from the hone during each operation although the amount removed is infinitesimal for each gear. Nevertheless, the small amount of removal of material of the hone theoretically calls for a slight angular adjustment of the tool head 32 as each new gear is replaced. As a matter of interest, it may be noted that during the life of a hone having an initial pitch diameter of nine inches and an initial helix angle of twenty degrees, the operating pitch diameter may be reduced to 8.800 inches, at which time the helix angle at the pitch diameter is 19 35' 23". Thus, during the life of the hone an angular adjustment of 24' 37" is required. If this angular compensating adjustment is made automatically at each gear finishing operation, the hone operates uniformly throughout its entire life and tendency for damage to the hone attributable to misalignment between the teeth of the hone and gear is completely avoided.

Instead of relying solely upon the forces developed between the teeth of the gear and hone, sine bar mechanism between the tool head 32 and tilt table 22 may be provided. Such mechanism may comprise a sine bar carried by the tilt table at a point positioned remote from the vertical axis of adjustment of the head 32, and

a follower 132 on the tool head, as seen in FIGURE 5.

The drawings and the foregoing specification constitute a description of the improved gear honing machine in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. A gear honing machine comprising a frame, a work support on said frame including a rotary spindle for a work gear, a tool support on said frame including a 1'0- tary spindle for a gear-like honing tool, a honing tool on said last mentioned spindle in the form of an abrasive helical gear subject to substantial wear in protracted use, means mounting one of said supports on said frame for traverse in a direction occupying a plane parallel to the axes of both of said spindles, swivel means mounting one of said supports for very free angular adjustment about an axis perpendicular to the axes of both of said spindles, means mounting one of said supports for movement toward and away from the other of said supports, means connected between said frame and said one support to bias said one support toward the other to bring the gear and hone into controlled pressure contact, and quick acting power actuated locking means to control movement of said swivel means to lock said swiveled support against angular movement after it has been swiveled into correct angular position by engagement between said gear and honing tool, and means for driving one of said spindles in rotation, said other spindle being freely rotatable.

2. A gear honing machine comprising a pair of rotary spindles for supporting a gear and gear-like hone in mesh at crossed axes, a honing tool on one of said spindles in the form of an abrasive helical gear subject to sub stantial wear in protracted use, means to urge said spindles together with a controlled force to determine the pressure between the teeth of the gear and hone, a swivel mounting for one of said spindles to provide angular adjustment thereof about an axis perpendicular to the axes of both of said spindles, said swivel mounting including anti-friction means to provide for angular movement of said one spindle under forces developed between the teeth of the gear and hone, means for driving one of said spindles in rotation, and quick acting power actuated means for locking said swivel mounting following movement of the gear and bone into pressure contact.

3. A gear honing machine comprising a pair of rotary spindles for supporting a gear and gear-like hone in mesh at crossed axes, a honing tool on one of said spindles in the form of an abrasive helical gear subject to substantial wear in protracted use means to urge said spindles together with a controlled force to determine the pressure between the teeth of the gear and hone, a swivel mounting for one of said spindles to provide angular adjustment thereof about an axis perpendicular to the axes of both of said spindles, said swivel mounting including anti-friction means to provide for angular movement of said one spindle under forces developed between the teeth of the gear and hone, means for driving one of said spindles in rotation, and means for locking said swivel mounting following movement of the gear and hone into pressure contact, said lock means comprising a power actuated friction brake.

4. A gear honing machine comprising a frame, a work support on said frame including a rotary spindle adapted to support a Work gear thereon, a tool support on said frame including a rotary spindle having a helical gearlike hone thereon which is subject to substantial wear in protracted use, means mounting one of said supports on said frame for traverse in a direction occupying a plane parallel to the axes of both of said spindles, means mounting one of said supports on said frame for movement toward and away from the other of said supports, means for driving one of said spindles in rotation, the other spindle being freely rotatable, said spindles being arranged to mount a work gear and bone in mesh at crossed axes, means connected between said frame and one of said supports to bias said one support toward the other with a controlled light force to determine the pressure between the teeth of the work gear and hone, a swivel mounting for one of said spindles providing for angular adjustment thereof about an axis perpendicular to the axes of both of said spindles, cam means separate from the gear and gear-like hone and responsive to relative approach between said spindles and hence effective to compensate for hone wear operable to effect angular adjustment of said swivel mounting, and quick acting power actuated lock means for locking said swivel mounting after said gear and hone have been brought into the proper angular relationship.

References Cited in the file of this patent UNITED STATES PATENTS 

